Jinghong Xiong a, *, Satoshi Muraki b
a Graduate School of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka City 815 8540, Japan
b Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka City 815 8540, Japan

Abstract

This study investigated the relationship between the movement coverage on smartphone touchscreens and the factors (age, thumb length and screen size) affecting this. By referring to the thumb movement in the adduction-abduction orientation with a right-hand phone-holding posture, the thumb-coverage area that represents how far the thumb can reach and the centre of gravity in this coverage area were determined. The assessment focused on a comparison of these indices between ages, thumb lengths and screen sizes. The results showed that elderly users and those with longer thumbs are likely to leave more unreachable space at the right side and bottom of touchscreens. Moreover, the thumb-coverage area actually increased when the touchscreen size was increased; however, increasing the size of a smartphone touchscreen does not necessarily increase the thumb-coverage area at the same ratio as the touchscreen size increases

  An ergonomic expert system for risk assessment of work-related musculo-skeletal disorders.pdf (اندازه 880.11 KB / تعداد دانلود: 87849)

Prakash Kumar a, *, Debkumar Chakrabarti a, Thaneswer Patel b, Anirban Chowdhuri a
a Department of Design, Indian Institute of Technology (IIT) Guwahati, Guwahati 781 039, Assam, India
b Department of Agricultural Engineering, North Eastern Regional Institute of Science and Technology (NERIST), Nirjuli 791 109, Arunachal Pradesh, India

Abstract

The present study aimed at investigating work-related pain issues among the workers associated with pineapple peeling activity in small fruit processing units of North East India. The study also assessed the associated levels of ergonomic risk prevalent among the workers and identified ergonomic risk factors associated with pineapple peeling task. A cross-sectional survey was conducted using questionnaire-based interview, pain self-report and direct observation of the activities to understand the prevailing work conditions. Rapid Upper Limb Assessment (RULA) was used to assess the level of ergonomic risks involved. Prevalence of pain, in different body parts of the participants, was found evident with a higher percentage of participants reporting pain in shoulders (41.1%), upper arms (37.1%) and lower back (45.7%) while some had also reported of pain in neck (13.2%), lower arms (15.9%), wrists (12.6%) and palm (6%). For RULA, 89.4% of the participants had a grand score greater than equal to 5 which fell under action level 3 indicating for further investigation and changes soon. Hence, various risk factors influencing pain occurrences were identified using logistic regression, and factors like age, gender, hours of peeling, frequency of rest breaks, perceived work fatigue and years of experience, were found to be associated with risk of pain in at least one of the body parts. Identification of these risk factors laid down path for the future course of actions and improvements to address the work pain related issues among workers

Relevance to industry

The study established pain prevalence associated with manual pineapple peeling task and identified the potential risk factors, laying down basis for possible future actions to address work pain related issues and enhance productivity of the workers.

Peter Mylon a, *, Roger Lewis a, Matt J. Carr
e a, Nicolas Martin b
a Department of Mechanical Engineering, The University of Sheffield, UK
b School of Clinical Dentistry, University of Sheffield, UK

Abstract

Understanding the effect of medical gloves on manual performance is critical for improving glove design and mitigating the impediment to surgical performance caused by gloves. Existing test methods do not correspond well with clinical and surgical tasks. Based on interviews with clinicians, two new tests were proposed: locating a pulse in a simulated blood vessel, and placing and tying sutures in simulated tissue. A pilot study was carried out using 19 clinicians employed at Sheffield Teaching Hospitals. Subjects performed each test three times, with latex and nitrile examination gloves, and without gloves, the order being randomised. In addition to objective test scores, subjects' perception of their relative performance in each condition was recorded. In the Pulse Location Test, performance was found to be significantly better without gloves, while differences between gloves were not statistically significant. Perceived performance correlated well with measured performance. In the Suturing Test, no statistically significant performance differences were found between the three hand conditions, although subjects perceived ungloved performance to be significantly better than with either the latex or nitrile gloves. The Pulse Location Test showed promise as a clinical performance evaluation tool, and could be used to improve medical glove design for better tactile performance. The discrepancy between subjects' perceived and measured performance in the Suturing Test needs further investigation to determine whether the perceived differences translate into genuine clinical performance differences that were not able to be measured using the current method, or whether the difference is purely psychological

Relevance to industry

The test methods outlined will allow manufacturers to understand the effect of gloves and glove properties on manual performance in medical tasks and improve the design accordingly. Reducing the inhibiting effect of gloves will improve safety and reduce the need to remove gloves for clinical tasks

  Single users' affective responses models for product form design.pdf (اندازه 1.74 MB / تعداد دانلود: 113)

Yumiao Chen a, Zhongliang Yang b, *, Jianping Wang a, Hugh Gong c
a Fashion Institute, Donghua University, Shanghai 200051, China
b College of Mechanical Engineering, Donghua University, Shanghai 201620, China
c School of Materials, The University of Manchester, Manchester M13 9PL, UK

Abstract

The objective of this study was to assess the impact of breathing resistance on physiological and subjective responses to N95 filtering facepiece respirators (N95 FFRs) during still-sitting and walking. Fifteen subjects sat for 5 min and walked for 5 min while wearing 2 different models of N95 FFRs, 1 model of which was equipped with exhalation valves (N95 FFR/EV). The subjects were monitored by a modified monitoring garment for respiratory signals (RSP) and surface electromyography (sEMG). Subjects also were asked to complete subjective ratings of overall breathing resistance. The results of the physiological measurements in this study have shown that compared with no respirator, wearing N95 FFR had a direct effect on increasing respiratory amplitude, muscle activity and fatigue of abdominal, and fatigue of scalene; The use of N95 FFR/EV conferred limited physiological benefit over N95 FFR in walking; Compared with sitting still, walking significantly decreased respiratory amplitude, but increased respiratory rate, the muscle activity of sternomastoid, scalene, diaphragm and abdominal, the fatigue of scalene and intercostal. The subjective survey showed that wearing respirators and walking had a direct effect on improving the subjective overall breathing resistance. Significantly low to moderate correlation coefficients were shown between physiological values (respiratory amplitude, the muscle activity of diaphragm, the muscle activity and fatigue of scalene and abdominal), and the subjective breathing resistance. This is the first reported study that combines RSP, sEMG and subjective overall breathing resistance to evaluate breathing resistance on the use of N95 FFR in sitting still and walking. The physiological responses to breathing resistance of wearing a N95 FFR for 5 min in still-sitting and walking are relatively small and should generally be well tolerated by healthy persons

Relevance to industry

This paper's findings can be readily employed by respirator manufactures and administrations for evaluating the respiratory muscle function (activity, fatigue) and breathing parameters of wearing N95 FFRs. Observations of present study are in support of issuing new regulations to raise the limit for breathing resistance over short periods at low-moderate exertion tasks. Thus, the manufacturers could easily fulfill the requirements for collection efficiency by adding more filter media while still meeting the requirements for air resistance

Paolo Lenzuni a, *, Roberto Deboli b, Christian Preti b, Angela Calvo c
a Italian National Workers' Compensation Authority (INAIL), Florence Research Unit, Florence, Italy
b Institute for Agricultural and Earth-moving Machines (IMAMOTER), Italian National Research Council, Turin, Italy
c Department of Agricultural, Forest and Food Sciences (DISAFA), University of Turin, Italy

Abstract

In this paper we present the outcome of a Round Robin test carried out to validate a proposed standard procedure to measure the acceleration produced by an hand held olive harvester. Ten independent laboratories using a custom-built device were involved. The device was developed to simulate olive tree branches as far as their interaction with the harvester sticks is concerned.

Collected data were analysed according to the ISO 5725-2 procedure. Accelerations measured in three of the ten laboratories were found by a cluster analysis to be statistically different from those of the remaining seven laboratories. Based on this evidence, results from the three stray laboratories were eliminated from the final sample.

Laboratory data were shown to be statistically consistent with field data in the dominant front and rear X axes as well as in the rear Z axis. No statistically significant discrepancy were found for the front and the rear acceleration vector sums, which are the quantities used to quantify the occupational exposure. The procedure developed in this Round Robin test could represent a viable basis for a future test standard for hand-held olive harvesters

Relevance to industry

Olive beaters are devices characterized by high vibration levels transmitted to the hand-arm system. Because of the lack of a harmonized C standard, manufacturers struggle to report reliable acceleration values in the instruction manuals, as requested by the 2006/42/EC Directive. This work could help EN working groups to draft a C standard for the measurement of vibration of hand-held olive beaters

R.T. Vyavahare a, *, S.P. Kallurkar b
a Department of Mechanical Engineering, SKN Sinhgad College of Engineering, Pandharpur 413304, Maharashtra, India
b Department of Mechanical Engineering, Atharva College of Engineering, Mumbai 400095, Maharashtra, India

Abstract

Agricultural workers and farmers in India perform most of the agricultural operations manually. Hence, for the design of farm equipments, hand tools and machinery involving human efforts, region specific anthropometric data is needed. A survey was conducted to collect anthropometric dimensions of male agricultural workers in the state of Maharashtra in India in the age group of 18–60 years. Almost 59 body dimensions were selected for the measurement from the recommendations by All India Coordinated Research Project (AICRP) on Human Engineering and Safety in Agriculture (HESA) and requisite by digital human manikin modeling. Total 303 male agricultural workers were selected from 23 districts of Maharashtra by convenience sampling. Repeatability of the measurements was checked by paired samples t test. From the measured dimensions, the values of minimum, maximum, mean, standard deviation (SD), standard error of mean (SEM), coefficient of variation (CV), 5th and 95th percentile values were determined. The results of the survey were compared with results of other regions of India and other countries

Relevance to industry

The anthropometric data of user population is very utile for the design/improvement of farm equipments/implements for agricultural workers in order to reduce drudgery, increase efficiency, safety and comfort

Amjad Hussain a, Keith Case b, *, Russell Marshall c, Steve Summerskill c
a Department of Industrial and Manufacturing Engineering, University of Engineering and Technology, Lahore, Pakistan
b Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
c Design School, Loughborough University, Loughborough, Leicestershire, UK

Abstract

The aim of this research study was to understand and evaluate the effect of different factors including age, gender, disabilities and medical conditions on joint mobility. Joint mobility data from a group of 66 people from a previously existing database has been re-analysed. Twenty four participants had disabilities and 42 participants were considered to be ‘able bodied’ with no recognised disability. For each individual, 18 joint range of motion values were measured and an ANOVA test was employed to demonstrate the influence of the selected factors on joint range of motion. Post Hoc (Tukey) tests were also performed to gain deeper insight into significance levels and correlations between the factors. The results clearly indicate that joint ROM significantly decreases (p < 0.05) with increasing age for arm abduction, arm medial and lateral rotation, wrist flexion and wrist adduction. Moreover, people with disabilities (wheelchair users and arthritis sufferers) showed a considerable decrease in joint mobility for arm flexion, arm abduction, arm lateral rotation, elbow flexion, elbow supination, wrist extension and wrist flexion. The results also highlight that designing products, equipment, services or workplaces against 5th and 95th percentile criteria is unable to provide appropriate and necessary support for achieving the objective of design inclusiveness. Rather designers should have a deep insight of the data variations at a predesign phase so that more appropriate and informed design decisions can be made that are more likely to be acceptable for a broad range of the population

Shahoub Sherif, Syed Hasan, Graham Arnold, Rami Abboud, Weijie Wang
Institute of Motion Analysis and Research, Department of Orthopaedic and Trauma Surgery, Tayside Orthopaedics and Rehabilitation Technology Centre
Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, United Kingdom

Abstract

Hand pressure in crutch is important as it is directly related to the comfort of the patients using crutches. However, little research has been done on dynamical hand pressure during crutched walking. This study investigated hand pressures and joint movements in the upper limb with the different crutch lengths during crutched walking. Twelve healthy male adults participated in the study, and performed crutch-supported walking at bi-crutch and single-foot way. A specific mat of pressure sensors was designed to measure the hand pressure of the palm and fingers and a motion capture system used to capture the movements at the shoulder and elbow. It was found that when walking speeds were between 0.5 and 1.0 m/s, maximum pressure and force were approximately 120 kPa and 100 N respectively in the hand; the ranges of motion were from 28 to 60 deg at the shoulder and from 15 to 30 deg at the elbow. The results showed that the pressure-time integral and force-time integral in the hand are higher when using a traditional standard crutch length than using longer or shorter lengths. The visual analogue scores of conformable degree showed that the participants are favourite for a traditional standard crutch length. The pressure and kinematic data collected provide a set of database available for crutch manufacturer, glove designer and clinicians as reference when they need

Relevance to industry

Crutched walking usually causes hand uncomfortable or injury. Our study provides the first experimental data of hand pressures and the joint movements in the upper limbs at different crutch lengths. These results are valuable for devising gloves for patients, thus improving the life quality of the patients using crutch

Matteo Savino a, Antonio Mazza a, Daria Battini b
a University of Sannio, Benevento, Italy
b University of Padua, Padua, Italy

Abstract

Earlier studies have demonstrated the strong relationships between manual assembly work with a high repetition level and the presence of repetitive strain injuries (RSI) or repetitive motion illnesses (RMI). Moreover, recent works have also correlated the high physical load level in assembly lines with an increased number of quality defects in finished products. Thus, the ergo-quality level of a manual workstation needs to be carefully monitored not only to respond to the legislation but first of all to ensure a high system productivity level in the medium-term perspective. The objective of this study was to develop and test a new easy-to-use postural assessment tool and its performance in a car component assembly system. The results show the promising potential of the methodology particularly when compared with the well-known OCRA method

Jiahong Song a, Xingda Qu b, *, Chun-Hsien Chen a
a School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
b Institute of Human Factors and Ergonomics, College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen, China

Abstract

In this study, a novel lifting motion simulation model was developed based on a multi-objective optimization (MOO) approach. Two performance criteria, minimum physical effort and maximum load motion smoothness, were selected to define the multi-objective function in the optimization procedure using a weighted-sum MOO approach. Symmetric lifting motions performed by younger and older adults under varied task conditions were simulated. The results showed that the proposed MOO approach led to up to 18.9% reductions in the prediction errors compared to the single-objective optimization approach. This finding suggests that both minimum physical effort and maximum load motion smoothness play an important role in lifting motion planning. Age-related differences in the mechanisms for planning lifting motions were also investigated. In particular, younger workers tend to rely more on the criterion of minimizing physical effort during lifting motion planning, while maximizing load motion smoothness seems to be the dominant objective for older workers

Relevance to industry

Lifting tasks are closely associated with occupational low back pain (LBP). In this study, a novel lifting motion simulation model was developed to facilitate the analysis of lifting biomechanics and LBP prevention. Age-related differences in lifting motion planning were discussed for better understanding LBP injury mechanisms during lifting

Xiaojing Zhou a, *, Jinxiang Chen b, Guohua Chen c, Zhengxu Zhao d, Yong Zhao e
a School of Instrument Science and Engineering, Southeast University, Nanjing 210096, PR China
b School of Civil Engineering, Southeast University, Nanjing 210096, PR China
c School of Information Science and Engineering, Southeast University, Nanjing 210096, PR China
d School of Computing and Informatics, Shijiazhuang Tiedao University, Shijiazhang 050043, PR China
e System Consulting Dept., Aimnext Inc., Minato-Ku, Tokyo 105-0013, Japan

This paper presents an efficient and convenient method for creating an anthropometric model of a real person. First, 3D surface body models based on orthogonal-view photographs are reconstructed, and then skeletal systems for the reconstructed models are matched. A total of 26 anthropometric data items are measured using the surface and skeletal models. Some anthropometric data are measured directly on the deformed surface models, whereas others are estimated from the matched skeletal systems by kinematic analysis. A comparison of the anthropometric data from the reconstructed model with data from the corresponding real person demonstrates that the methodology proposed in this paper has high efficiency and precision. These models will satisfy consumer demand for higher product personalization and therefore product comfort, and they are likely to be widely used in future ergonomic research

A convenient and efficient method to create individual anthropometric models is proposed. These models will help people create their own anthropometry databases and satisfy their demand for higher product personalization and therefore product comfort. The industrial applications include mass customization, computer-aided drafting, online custom-made design, and ergonomic evaluation

Federica Caffaro a, Margherita Micheletti Cremasco b, Christian Preti a, Eugenio Cavallo a

a Institute for Agricultural and Earthmoving Machines (IMAMOTER), National Research Council (CNR) of Italy, Strada delle Cacce, 73, 10135, Torino, Italy

b Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina, 13, 10123, Torino, Italy

Introduction
Exposure to whole body vibration (WBV) is one of the most important risks for musculoskeletal disorders (MSDs). The objective of the study was to investigate whether an active cab suspension system fitted on a telehandler was effective in reducing WBV and in improving comfort

Method
Sixteen male healthy professional operators drove a telehandler on a 100 m ISO 5008 smooth track at two different speeds (5 and 12 kph) with activated and deactivated cab suspension system. Adopting an ergonomic approach, different aspects of the human-machine interaction were analyzed: 1) vibration transmissibility, 2) subjective ratings of general comfort and local body discomfort, and 3) anthropometric characteristics of the users

Results
A series of ANCOVAs showed that the suspension system was effective in reducing WBV at both speeds but did not affect the perception of comfort by the operators. Moreover, individuals with higher Body Mass Index (BMI) experienced more comfort. Some neck/shoulder and lumbar complaints and perceived hard jolts seemed to remain even when the system was activated. No correlations were found between objective and subjective measures
Practical applications
Results suggest that the operators, given their wide range of physical variability, may need more adjustable or customizable WBV reduction systems

Soo-chan Jee, Myung Hwan Yun*

Department of Industrial Engineering, Seoul National University, San 56-1 Silim Dong, Kwanak Gu, Seoul, 151-744, South Korea

Abstract

Some tools or interfaces designed not to fit the size of individuals make users experience discomfort and lower productivity. Previous studies on hands tend to focus only on measuring lengths of various hand parts and reporting the distribution of these measurements. In order to overcome this, we aim to distinguish major factors that determine hand shapes and categorize the hand shapes of Koreans. 321 people (167 males and 154 females) enrolled as subjects of this study by their own will. 21 hand dimensions including length, breadth, and circumference of the hand were measured. T-value and correlation coefficients were compared to identify the difference of measurement values and the relation between hand measurements and heights. Factor and cluster analysis was conducted to identify hand shape types of Korean. Descriptive statistics of Korean hand dimension were presented. 78.3% of the variance of hand shape was explained by 3 major factors (factor 1: hand breadth, factor 2: palm length, factor 3: finger length). We also distinguished 4 hand shape types and found that wide hand and short finger type (type 1) was the most common in males, but narrow hand and short finger type was the most common in females. Korean males and females had wider hands and shorter fingers than the people of 8 other nations. We expect products and interfaces to be designed based on these understandings on the characteristics of Korean hands that the result of our study suggests

Sisay A. Workineh*, Hiroshi Yamaura

Dept. of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 158-8552, Japan

Abstract

This paper presents a new design of computer workstation that is aimed at increasing the comfort of a user working for long periods at a computer. As we have become a society that spends a lot of time working on computers, the computer workstation needs to provide comfort to users. Discomfort and an improper position can negatively affect overall health and productivity. A new type of ergonomic computer workstation, which allows users to sit in multiple working positions, is proposed in order to provide better comfort to people who spend a long time sitting at their workstations. We have designed and developed a new multi-position ergonomic computer workstation which has 19 degrees of freedom and which can accommodate from 5th to 95th percentile human size. Four types of working position (upright, lean-back, zero-gravity and lean-forward) are preset by choosing different angular positions of the workstation parts. Positions of the workstation parts can be changed by controlling the actuators. These four positions were used to evaluate the comfort of the workstation. Subjective and objective evaluations, including comparison of the prototype and standard computer setup, were carried out using human subjects and ergonomic principles. Results showed that the new workstation is much more comfortable, supporting the body in a balanced way. Users have the freedom to stretch and relax in different working positions before they feel any noticeable discomfort; as a result, it lets users work for a longer period without strain, thus resulting in higher productivity

  Multi-position ergonomic computer workstation design to increase comfort of computer work.pdf (اندازه 1.89 MB / تعداد دانلود: 29775)